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 approval is obtained from Code 04CN.EH for a level of retrofit performance beyond "Life
Safety." The design criteria for such enhanced performance upgrades will be assigned at
the time a decision is made to design for enhanced performance.
6.8.3.1 Ground Motion: Site characteristics may be determined from previous
Geotechnical (Soils Investigation) reports if adequate information is available.
Determination of the "Site Class" as defined in Table 3-1 of TI 809-04 or section 4.1.2.1
(Site Class Definitions) of FEMA 302 shall be made by a geotechnical engineer.
Determination of Fa and Fv shall not be made without a geotechnically established site
class. Minor projects that do not require a geotechnical report may use the FEMA 302
default site classification D.
a. Site specific determination of seismic ground motion shall be based on the
guidelines presented in chapter 3-4 of TI 809-04. Note that a peer review is
required for site specific ground motion determination as defined in section 3-4.b
of TI 809-04.
b. Refer to section 3.6 of the A-E Guide for additional information concerning
site specific ground motion representation.
6.8.3.2 Architectural, Mechanical, Electrical and Other Nonstructural Components Design:
Seismic rehabilitation shall include anchorage and restraint of all equipment that is not
adequately anchored. As a minimum, all new anchorage design shall be based on the
requirements for Seismic Design Category D of FEMA 302.
a. Seismic anchorage and restraint details shall be provided for all equipment that
exceeds 400# (180kg) in weight. If exact weights and dimensions are unknown,
details shall be based on the best information available, and may be modified
during construction if original design assumptions prove to be inaccurate.
b. Support and seismic restraint shall be detailed for all ducts, pipes,
suspended equipment etc. Reference to generally accepted standards such
as
the "SMACNA Guidelines" are acceptable for ordinary installations.
c. Support and seismic restraint of all ceiling systems shall be detailed. Details to
include compression struts at all locations where diagonal splay bracing
occurs.
6.8.3.3 Foundation Design: As a minimum, all new foundation design for seismic
rehabilitation shall comply with section 7.5 (Seismic Design Categories D,E & F) of FEMA
302.
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